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Introduction Thoughts or feelings in language are often conveyed through expressions; however, mathematical ideas are conveyed through algebraic expressions. Algebraic expressions are mathematical statements that include numbers, operations, and variables to represent a number or quantity. Variablesare letters used to represent values or unknown quantities that can change or vary. One example of an algebraic expression is 3x – 4. Notice the variable, x. 1.1.1: Identifying Terms, Factors, and Coefficients
Key Concepts Expressions are made up of terms.A term is a number, a variable, or the product of a number and variable(s). An addition or subtraction sign separates each term of an expression. In the expression 4x2 + 3x+ 7, there are 3 terms: 4x2, 3x, and 7. The factorsof each term are the numbers or expressions that when multiplied produce a given product. In the example above, the factors of 4x2are 4 and x2. The factors of 3xare 3 and x. 1.1.1: Identifying Terms, Factors, and Coefficients
Key Concepts, continued 4 is also known as the coefficientof the term 4x2. A coefficient is the number multiplied by a variable in an algebraic expression. The coefficient of 3xis 3. The term 4x2 also has an exponent. Exponents indicate the number of times a factor is being multiplied by itself. In this term, 2 is the exponent and indicates that x is multiplied by itself 2 times. Terms that do not contain a variable are called constants because the quantity does not change. In this example, 7 is a constant. 1.1.1: Identifying Terms, Factors, and Coefficients
Key Concepts, continued 1.1.1: Identifying Terms, Factors, and Coefficients
Key Concepts, continued Terms with the same variable raised to the same exponent are called like terms. In the example 5x+ 3x – 9, 5x and 3x are like terms. Like terms can be combined following the order of operations by evaluating grouping symbols, evaluating exponents, completing multiplication and division, and completing addition and subtraction from left to right. In this example, the sum of 5x and 3xis 8x. 1.1.1: Identifying Terms, Factors, and Coefficients
Common Errors/Misconceptions incorrectly following the order of operations incorrectly identifying like terms incorrectly combining terms involving subtraction 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice Example 2 A smartphone is on sale for 25% off its list price. The sale price of the smartphone is $149.25. What expression can be used to represent the list price of the smartphone? Identify each term, coefficient, constant, and factor of the expression described. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 2, continued Translate the verbal expression into an algebraic expression. Let x represent the unknown list price. Describe the situation. The list price is found by adding the discounted amount to the sale price: sale price + discount amount The discount amount is found by multiplying the discount percent by the unknown list price. The expression that represents the list price of the smartphone is 149.25 + 0.25x. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 2, continued Identify all terms. There are two terms described in the expression: the sale price of $149.25, and the discount of 25% off the list price, or 149.25 and 0.25x. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 2, continued Identify the factors. 0.25xis the product of the factors 0.25 and x. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 2, continued Identify all coefficients. 0.25 is multiplied by the variable, x; therefore, 0.25 is a coefficient. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 2, continued Identify any constants. The number that does not change in the expression is 149.25; therefore, 149.25 is a constant. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 2, continued ✔ 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice Example 3 Helen purchased 3 books from an online bookstore and received a 20% discount. The shipping cost was $10 and was not discounted. Write an expression that can be used to represent the total amount Helen paid for 3 books plus the shipping cost. Identify each term, coefficient, constant, and factor of the expression described. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice:Example 3, continued Translate the verbal expression into an algebraic expression. Let x represent the unknown price. The expression used to represent the total amount Helen paid for the 3 books plus shipping is 3x – 0.20(3x) + 10. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 3, continued Simplify the expression. The expression can be simplified by following the order of operations and combining like terms. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 3, continued Identify all terms. There are two terms in the described expression: the product of 2.4 and x, and the shipping charge of $10: 2.4xand 10. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 3, continued Identify the factors. 2.4x is the product of the factors 2.4 and x. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 3, continued Identify all coefficients. 2.4 is multiplied by the variable, x; therefore, 2.4 is a coefficient. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 3, continued Identify any constants. The number that does not change in the expression is 10; therefore, 10 is a constant. 1.1.1: Identifying Terms, Factors, and Coefficients
Guided Practice: Example 3, continued ✔ 1.1.1: Identifying Terms, Factors, and Coefficients